<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>延迟显示元素</title>
</head>
<body>
<div id="change" class="change">
  <h1 style="background-color: red">Hello, World!</h1>
  <h1 style="background-color: green; display: none">Hello, Vue!</h1>
</div>

<script>
  let element = document.querySelector("#change > h1:nth-child(2)");

  setTimeout(()=>{
      // 注意：没有特殊情况，尽量不要删除 style 属性
      // element.removeAttribute("style")
      element.style.display = "block"

  }, 3000)


</script>
</body>
</html>